The present invention relates to means to provide an improved fuel burning element, such as a candle or lamp, which consumes fuel more efficiently while presenting an improved means for distribution of volatile materials, while also providing an improved degree of safety while burning, and a candle holder which requires little or no cleaning to remove wax residue. The candles or lamps of the present invention comprise a solid fuel element located on a melting plate, a preferably consumable wick, and heat conductive means in the wick holder to transfer heat from the burning fuel, i.e. the flame, to the remaining fuel, thereby assuring its more rapid and complete melting, and both control and uniformity of the temperature of the melted pool of fuel. The melting plate incorporates a capillary lobe which cooperatively engages either or both of the wick holder and the fuel element in such a manner as to assure exact placement of both at the best position on the melting plate, while creating a capillary effect to feed melted fuel to the wick for efficient consumption. Such a configuration has been found to provide improved means to control the transfer of heat generated by a candle flame, and to provide an improved degree of safety for the burning of candles, such as votive candles. Specifically, the preferred embodiment of the present invention comprises the use of a capillary lobe at or near the center of the melting plate of a melting plate candle, said capillary lobe cooperatively engaging a complimentarily shaped wick holder having a heat conductive fin. By virtue of this combination of capillary lobe and cooperative wick holder, applicants have provided a candle in which the flame of the candle remains essentially at the same height, relative to the surface upon which the candle holder is placed.
Ordinary candles comprise a vertical, self-supporting body or column of wax, with a substantially horizontal top and a central longitudinal wick which extends through and above the wax. The exposed portion of the wick above the solid wax is lighted by a flame, and the heat generated by the flame melts a small volume of the wax at the top of the candle, adjacent the wick, establishing a puddle or reservoir of molten wax to serve as fuel for the flame on the wick, and to release any volatile actives present therein. The capillary attraction of the molten wax and the wick, which is generally a structure of closely related fibers, causes the molten wax to travel through the wick to the flame, by which it is consumed. As the wax is consumed in this manner, the body of wax diminishes and the top surface thereof progressively lowers. The upper portion of the wick, extending above the lowering wax, is generally consumed by the flame. The flame in such a candle remains in the same position relative to height, from the start to the end of the burn, at which time all of the wax has been consumed.
Also well known are such candles as votive candles and tea lights. For purpose of discussion, tea lights shall be considered to be relatively small candles in which a body of paraffin is located in a container, having a wick centrally disposed, while votive candles shall be considered to be candles of similar size provided without a container. At the lower end of the wick is typically found a wick clip having a flat horizontal bottom surface, which functions to retain the wick in its perpendicular position, even as the paraffin is melted and liquified by the heat of the flame. In most such votive candles and tea lights, the wick is a cotton material saturated with paraffin, and burns with the paraffin, thus being consumable. In such candles, or lights or warmers employing the same, the visible flame moves lower, or closer to the bottom surface of the container as the fuel and wick are consumed, down to the level of the bottom of the wick. Further, after consumption of all of the wax above this point in the unit, the container (of the tea light), the unburned wax, and the wick clip remain to be disposed of by the consumer. As a safety consideration in such candles, the wick is normally crimped or terminated at a point about 0.25 inches above the bottom of the wax, so as to cause the flame to extinguish above the bottom of the container, and to thus prevent the heat of the flame from reaching the surface upon which the candle is positioned, preventing damage to such surface, and reducing the likelihood of igniting possible contaminants such as burnt matchsticks remaining at the bottom of the candle, or carbonaceous remains of the consumable wick. Such an arrangement also has the detriment of leaving a small volume of unburned wax in the bottom of the container when the flame extinguishes.
Similarly, liquid fuel lamps are known in which a wick is supported with one end suspended in a reservoir of liquid fuel, such as lamp oil. By capillary action, the liquid fuel rises through the wick to the upper end thereof, where it is subjected to consumption by a flame. As fuel is consumed by the flame, additional fuel rises through the wick by capillary action to feed and maintain the flame. Permanent, or non-consumable, wicks are most frequently employed for this type of lamp.
In U.S. Pat. No. 4,557,687, Schirneker teaches a fuel element comprising a shell-like elongated housing in which a supply of fuel may be placed, with a non-consumable wick immersed in the fuel supply with its upper portion protruding from the top of the housing. When the fuel is a solid fuel, such as paraffin, the wick must conduct heat into the housing of the fuel in the area of the immersed wick to thereby melt the solid fuel so as to provide sufficient amounts of molten paraffin to be drawn up in the wick. Such conductivity may be obtained by means of a piece of metal embedded in the wick. The purpose of the fuel element is to provide a simulated log for a fireplace which does not require a chimney.
Neil, in U.S. Pat. No. 4,206,500, teaches a candle having a metal stiffener which fits within the wick. The stiffener is supported by a flat base portion large enough to render the wick free-standing by supporting the weight of the nonconsumable wick.
In U.S. Pat. No. 3,741,711, Bryant teaches a composite decorative candle formed of clear, undyed and unpigmented candle wax in any appropriate candle shape, provided with a centrally recessed glass cylinder into which a replaceable small candle may be placed. Thus, the decorative outer candle may have a refill unit, such as a votive candle or tea light, placed therein to provide indefinite reusability. If the outer candle body comprises surface ornamentation, a luminescent glow through the candle body results when the inner candle is burned, and the outer candle is not consumed.
U.S. Pat. No.3,910,753, of Lee, discloses a wax burner comprising a vessel having a heat conducting metal heat sink surrounding and supporting a wick which projects upwardly, and has a heat conductive metal core means conducting heat into the heat sink, which acts as a wax melting surface. The wax burner may be fueled by paraffin wax or other suitable solid fuel, which may be added to the melting surface as required. The burner may constitute one or more units. In Lee, however, the fuel is neither supported nor contained by the heat sink, which is configured much like a spool, with upper and lower flanges, or upper and lower flat horizontal surfaces. The upper flange or upper surface acts as a heating surface, while the lower flange serves as a base for the heat sink, engaging the bottom surface of the burner vessel. Slots in the vertical surface of the heat sink provide means for the wax, melted by the heat sink, to flow from the exterior surface thereof to the internally located wick. Since the wick structure of the patent includes a metal core and a heat conductive metal sleeve about the wick, the wick structure is an integral portion of the heat sink of the burner assembly, is non-consumable, and requires priming with wax prior to its first use. In use, solid wax is added to the heating surface, and replenished as necessary, or the entire vessel may be filled with wax. It is to be noted that the vessel itself is not used to conduct heat to the fuel, but only to contain it, and that a separate heat transfer system, i.e. the heat sink structure, which is independent of and distinct from the heat radiated by the flame itself, is utilized to achieve burning of the wax fuel. Even with this added heat transfer mechanism to assist in melting of the fuel, complete utilization of all of the fuel in the vessel is unachievable, even when the burner is permitted to burn to self-extinction, in view of the relative positioning of the lower flange and the wax conducting means of the heat sink (i.e. slots in the vertical surface thereof, above the lower flange).
In U.S. Pat. No. 2,713,256, Oesterle et al teach a votive candle having a wick extending downward in the bottom of the candle into a tapered central body projection, where said wick engages an adapter inserted into a cup provided to hold the votive. The adapter is provided with means to support the wick of the candle until the candle has completely burnt out, thereby leaving no wax or wick residue in the cup, enabling a new candle to be inserted into the cup without removal of the adapter. The adapter does not function to provide a more even or uniform burning of the candle, but merely to provide a proper positioning of the votive candle. When placed over the adapter, and the upwardly directed tube thereof, the flame on the wick comes into contact with a wicking material retained in the base of the tube, so as to ignite such wicking and assure that all of the melted wax is burned, thus leaving a clean cup containing no remains of the previous candle when a new candle is put in place.
European Patent Application EP 1 054 054 A1, published Nov. 22, 2000, teaches a candle having a wick holder assembly for candles to be used on a supporting surface, wherein the wick holder provides enhanced control over heat transfer form the flame to the supporting surface upon which the candle rests. In this patent, the object of the wick holder assembly is to dissipate heat from the flame away from the support surface, essentially the opposite of the goal of the present invention.
A number of additional patents teach the use of heat conductive elements to liquify solid fuel for consumption at a wick, or to dispense an element such as a fragrance or insect control material. These include U.S. Pat. No. 5,078,591 of Despres; U.S. Pat. No. 4,755,135 of Kwok; and U.S. Pat. No. 5,425,633 of Cole; as well as PCT Application WO 89/06141, assigned to Lamplight Farms, Inc. In addition, numerous patents teach various modifications of candles, but fail to teach the combination set forth in the present invention.
The present invention provides a candle or lamp device capable of rapidly and completely melting a solid fuel to form a large liquid pool, thereby improving distribution of any volatile materials present in the fuel, and ensuring efficient and complete utilization of all of the fuel provided, while providing increased safety and convenient refilling. Further, the concept of the present invention offers highly decorative as well as functional candles and lamps, which may utilize a variety of gel and solid fuels, with the significant advantages of permitting rapid and convenient replacement of one fuel element by another at the whim of the consumer, without the need to clean or scrape the container in which said candle is utilized to remove a body of unburned fuel after the fuel element has been consumed.